The adult formula of the tetanus and diphtheria toxoids and acellular pertussis vaccine (Tdap) can be given to children and adolescents starting at 18 months after a children's formula tetanus and diphtheria vaccine, said Dr. Scott A. Halperin of Dalhousie University, Halifax, Nova Scotia, and his colleagues.
Prior recommendations for a 10-year waiting period between doses of the tetanus and diphtheria toxoid-containing vaccine for infants and young children (TD) or the vaccine for older children and adults (Td) had been based on effectiveness rather than a lack of safety information, the investigators noted.
Concerns about the timing of vaccinations and adverse events prompted an open-label clinical trial including 7,156 children in grades 3–12 who received Tdap at time intervals ranging from 18 months to 9 years after their previous vaccinations with TD, Td, or diphtheria-tetanus-acellular pertussis (DTaP).
Tdap was generally well tolerated regardless of the time elapsed since the previous vaccination. Data on fever, injection site erythema, swelling, and pain were solicited for 14 days after immunization, and unsolicited adverse events were recorded for 28 days (Pediatr. Infect. Dis. J. 2006;25:195–200).
Overall, more than 80% of the children in each time interval reported injection site pain, but this was not significantly different from pain reports in children who were vaccinated 10 years after a previous immunization. Injection site erythema was slightly increased among children whose previous vaccine had been DTaP, but not among those whose previous vaccine had been Td. The four reported serious adverse events included one case each of asthma, bronchospasm, syncope, and juvenile onset diabetes mellitus, but none of these were attributed to Tdap.